A gas turbine requires its fuel to be pumped or compressed to sufficient pressure for injection into the combustion chamber. Combustion chamber pressure, commonly in the range of 10 to greater than 20 atmospheres, is determined by air compressor discharge pressure and other turbine design parameters. Work required to operate the pumps and/or compressors reduces the net work output from the gas turbine cycle. In addition, water or steam is often introduced into the fuel or fuel/air combination within the combustor for NOx control, and/or increased work output from the turbine. Such added water or steam must also be at sufficient pressure for entrance into the combustor. Again, the work required to operate pumps and/or compressors for these fluids reduces the net work output from the gas turbine cycle. Also, the extraction of medium pressure steam from the steam side of a combined cycle reduces the net work output from the combined cycle power plant. These details add considerable complexity to system controls, and their capital equipment cost and ongoing operation and maintenance expenses are significant.
In addition to the pressurization requirement, fuel, air, and water streams must be properly mixed for proper combustion. Scores of existing patents addressing these issues are evidence of the intense and ongoing efforts within the industry to improve upon existing technologies.
U.S. Pat. No. 5,617,716 details a method of vaporizing liquid fuel oil and combining it with steam for combustion in a gas turbine system.
U.S. Pat. No. 5,054,279 describes a system wherein steam, water and fuel are combined with gas in a combustor and the steam/fuel ratio is greater than 2.75 to 1.
U.S. Pat. No. 4,110,973 involves a design for blending a homogeneous mixture of liquid fuel and water for delivery to a gas turbine engine.
U.S. Pat. No. 4,259,837 details a control system for mixing water and fuel in a proper proportion for a gas turbine power system.
U.S. Pat. No. 4,089,639 describes a system for mixing gaseous fuel, air, and water for combustion.
U.S. Pat. No. 5,816,041 details a venturi type mixing nozzle for a gas turbine engine wherein gaseous fuel, air and water are mixed prior to their injection into the combustor.
U.S. Pat. No. 3,921,389 involves a means for combustion of hydrocarbon fuel with air and water.
U.S. Pat. No. 3,741,712 details a supply system for burning of emulsions of water and hydrocarbon fuel.